Electronic devices can convert an image obtained by photoelectric converting devices of camera modules such as a charge coupled device (CCD) or complementary metal-oxide semiconductor (CMOS), and output a preview image by performing a specific image processing for a photo-electrically converted image signal. The camera module included in such electronic devices can detect brightness of a subject image and perform an exposure function for adjusting brightness of an output image according to the brightness of the subject image. For a more accurate exposure function, the electronic device can receive a user input for selecting a specific area from a preview image and adjust an exposure of the preview image based on a brightness value of the specific area according to the user input.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.